"Americans really do leave their houses when there's more sunlight after work," he says. "But here's the problem: We're told we're saving energy, but when Americans go outside and go to the park and go to the mall, we don't walk—we get in our cars and drive. So for the past 100 years, the dirty secret is daylight saving increases gasoline consumption."

Nota: http://www.wnyc.org/.../who-really-benefits-daylight.../

On the basis of a traffic analysis made by means of the multiple regression method, it has been shown that the daylight saving time applied in summer months, causes a rise in evening traffic and creates an increase in fuel consumption and hence a higher pollution level in the atmosphere resulting from the products of fuel burning (NOx, volatile organic compounds). It has also been demonstrated — by using the recent version of the US EPA lagrangian EKMA trajectory model — that an increase in primary pollutants and the ‘shifting’ of traffic intensity with respect to sunlight intensity (UV) resulting from the launching of daylight savings time lead to a rise in secondary pollutants, especially in photochemical pollutants: ozone (O3) and peroxy acetyl nitrate (PAN).